1. Field of the Invention
The present invention relates to an electrical connector, and particularly to a high speed electrical connector having plural circuit board modules.
2. Description of Related Art
With the development of communication and computer technology, high density electrical connectors with conductive elements in a matrix arrangement are desired to construct a large number of signal transmitting paths between two electronic devices. Such high density electrical connectors are widely used in internal connecting systems of severs, routers and the like requiring high speed data processing and communication.
Due to continuing trends toward miniaturization and improved electrical performance by the electronics industry, requirements for greater contact density and higher electrical speeds are constantly being promulgated. This results in an increasing number of signals in the limited space of the connector. As the signal circuits are spaced closer and the transmission speed of the signals increases, electromagnetic inference (EMI) and the crosstalk become a serious problem.
U.S. Pat. Nos. 6,171,115 and 6,267,604, both issued to Mickievicz et al., each disclose a high speed connector having plural individual circuit boards to reduce crosstalk. The connector comprises a front housing portion having a front wall with a plurality of parallel apertures extending therethrough, and an organizer attached to the front housing portion to retain the plural individual circuit boards therebetween. The organizer has a plurality of spaced slots located corresponding to the apertures, and a plurality of openings communicating with the slots in a bottom wall thereof. The circuit boards have mating portions extending through the apertures of the front housing portion for mating with a complementary connector, and mounting edges received in the slots of the organizer. The mounting edges of the circuit boards have a plurality of terminals secured thereon by soldering. The terminals extend through respective openings of the organizer for electrically connecting with a circuit substrate.
U.S. Pat. No. 6,083,047 issued to Paagman, discloses a high speed connector having plural terminal modules retained to an insulating housing thereof. Each of the terminal modules comprises a dielectric cover and a printed circuit board (PCB) assembly associated with the dielectric cover. The PCB assembly includes an insulating substrate having a mating edge and a mounting edge perpendicular to each other, a plurality of circuit traces extending from the mating edge to the mounting edge, a plurality of socket terminals soldered to the mating edge for engaging with a complementary connector, and a plurality of press-fit terminals soldered to the mounting edge for connection to a printed circuit board on which the connector is mounted. Each press-fit terminal has a compliant tail which can be compressed upon insertion of the press-fit terminal into a corresponding through hole of the printed circuit board and then tends to restore to its original shape to engage surfaces within the through hole to thereby hold the connector on the printed circuit board. The press-fit terminal with a high retention force typically requires a high insertion force, which results in that the press-fit terminal is easy to deflect during the insertion of the press-fit terminal into the through hole of the circuit board. As a result, the connector is unreliably positioned on the printed circuit board and an electrical connection is adversely affected between the connector and the printed circuit board.
On the other hand, there exists a common disadvantage in the above-mentioned patents that the electromagnetic interference are still not solved. The high speed electrical connector equipped with shielding to reduce EMI can be referred to U.S. Pat. No. 5,980,321 (hereinafter the '321 patent). The connector disclosed in the '321 patent comprises a plurality of wafers side-by-side stacked and a metal stiffer holding the wafers in a required position. Each wafer is made in two pieces, a shield piece and a signal piece. The shield piece is formed by insert molding housing around a front portion thereof. The signal piece is made by insert molding housing around contacts. In order to hold each wafer in the required position without rotation, three connection points are established between the metal stiffer and the wafer. The connection comprises projections formed on the wafer and corresponding slots defined in the stiffer. However, the projections must be accurately aligned with corresponding slots, respectively, thereby complicating the manufacture of the connector as well as the assembly thereof. Further, the arrangement of positioning the shield pieces between the adjacent signal pieces reduces the effective signal density.
Hence, an improved electrical connector is required to overcome the disadvantages of the related art.